The Role of Surface Chemistry of Modified MWCNT on the Development and Characteristics of Pt Supported Catalysts

The performance and stability of electrocatalysts strongly depend on the physicochemical characteristics, such as the surface area, the crystalline structure, size and shape of the particles and the interactions with the support. Platinum (Pt) is one of the most versatile elements in catalysis, efficiently mediating a multitude of chemical reactions. Reducing the demand for expensive Pt is a major driving force in catalysis research. The objective of the present study is the development of electrocatalysts with innovative features and focuses on the synthesis and characterization of highly dispersed Pt supported catalysts using functionalized Multi-Wall Carbon Nanotubes (f-MWCNT) as the substrate. The choice of the substrate was based on the unique properties of carbon nanotubes that generate strong interest for their use in many nano-material devices in catalysis, batteries, optics, gas storage, electronics, sensors and others. Various chemical pathways were used to modify the sidewalls of MWCNT and introduce several covalently attached groups like pyridine, sulfonic acid, carboxyl, benzene or zwitterion type moieties. Using these substrates, deposition of Pt nanoparticles was realized by means of the polyol synthetic procedure. The parameters of the synthetic procedure differentiate the reduction/deposition mechanism. The surface chemistry and functionalities of the support and the diverse reaction conditions resulted in differentiations of the properties, not only in terms of quantitative deposition, but also with respect to platinum oxidation state, nanoparticle size and dispersion and overall catalyst morphology. The combined characterization techniques used shed light into the fundamental understanding of the support effect on the final properties, while metal-support interactions are intensely discussed.